Propeller



Sept. 27, 1960 vO. A. SKARSTEN ETAL PROPELLER Filed Das. 2 1955 Bukk G.Corleton Olav A.Skarsten INVENTORS ATTORNEYS PROPELLER Olav A. Skarsten, 624 E. 20th St, New York, N.Y., and Bnkk G. Carleton, New Canaan, Conn.; said Carleton assignor to said Skarsten Filed Dec. 2, 1955, Set. N0. 550,530

2 Claims. (C1. 170-159) This invention relates to fluid propulsion and in particular provides a ropeller hav-ing pantieular utility, when driven mechanically against the resistance of a fluid, in =the propulsion of vessels through such fluid o1 ior projecting a blast cf such fluid. This invention in particular provides an eflicient ropeller which is parficular provides an eflicient propeller which is partic-ularly olraracterized by the fact that it requires a much smaller diameter than is mequired with eonventional screw propellers to aecomplish the same thrust, and which is further characterized by high eflicieney in couversion of torque -*to thrust.

lt is believed that =the high efi.iciency and smaller diameter requirement of the propeller of this dnvention is a-t least in part =tl1e result of a unique manner of combining -tl1e streams of fluid gathered by eaeh blade into a single united, ejected stream having an area substantially less than the sum of stream areas upon whieh the blades initially act.

Broadly speaking, the propeller of this invention includes a pair of blades having obtuse angled, semi-conic surfaces mounted together at their apices on a shaft with one blade disposed 011 each side of the sha-ft with its conic axis tilted -rearwardly and ontwardly from the conic axis of the other, such that the pair of semi-eonic blade surfaces provide leading edges perpendicular to the axis cf the sha.f-t and aligned with each other 011 opposite sides 01 the shaft, and such that the trailing edge of each blade leads into the center et the other b1ade and is approximately coincident with the eonic axis of the other blade.

With fl1is manner of construetion in a marine prop'eller, as the propel-ler -is rotated to advance the leading edges of the two blades, a stream of water is soooped up by each blade and united with the stream of water gathered by the other blade and ejected producing a rearward F01 a more oomplete nnderstanding of this invention reference is made in the appended drawing in which:

Fig. 1 is an end view cf a propeller cnstructed in accordance with the principles this invention showing the trailing and leading edges of the blades lying in a plane crevolved 30 oounterclockwise from the vertica-l;

Fig. 2 is a side elevation of the propel-ler shown in Fig. 1 having the blades in the same osition as shown in Fig. l;

Fig. 3 is an elevational view of. the same propeller shown in Figs. 1 and 2 with the trailing and leading edges of the blades lying in a horizontal plane, tl1-at is the propeller has been revolved 120 in its normal di- 2 rection ef rotat-ion (clockwise in Fig. 1 from the positinn showinFigf2; and

Fig. 4 is a view of the pmpeller shown in Figs. 1-3 revolved 30 in the normal direction of rotation from the position shown in Figs. 1 and 2 and With the nearer blade removed.

In the drawings the reference numeral 10 generally desi-gnates a ropeller construeted in -aecordance with th-is invention, including a pair of identical blades 11 and 12 mounted on the stub 13 of a drive shaft 14. Bach blade 11 and 12 is a. half surface of a eone having an apex angle )f 120 cut oft by a plane perpendic-ular to the axis of the cone.

Referring mo re particularly 10 blade 11 conic blade 11 is provided with -a straight leading edge 15 whieh, at i-ts inner end, intersects the inner end of a straight trailingedge 16, the length of which is identical with that of leading edge 15. The angle of intersection of edges 15 and 16 is 120. The outer ends of leading and trailing edges 15 and 16 1ie at opposite ends of semicircular outer edge 17 which lies in a plane perpendieular to rthe plane determined by intersecting edges 15 and 16.

Blade 11. thus enclosed between edges 15, 16 and 17 -is half of a 120 conic surface wit-h its a-pex at the point of intersection cf edges 15 and 16, aflixed in stub 13. Leading edge 15 and trailing edge 16 lie in a plane which eoincides with (the ax-is of rotation of shacfit 14, leading edge 15 1ying at an angle of to the axis of rotati0n and trailing edge 16 lying at an angle of 30 to such axis of rotation.

Blade 12 has the identical shape of bl-ade 11 an has a leading edge 18, a trailing edge 19 and an outer edge 20 which define between them half of a conic surface similarly aifixed at i1:s apex in stub 13, but disposed on the opposite side of shaft 14 from bl-ade 11. Leading edge 18 and trailing edge 19 also lie in =1zhe same plane 1as edges 15 and 16 of blade 11 but edge 18 is disposed on the opposite side of the axis of rotation from edge 15, and similarly edge 19 is disposed on the same side of the axis of rotation as edge 15, but opposite corresponding trail-ling edge 16.

It will =be observed, beeause of =the angles in the pa1= ticular 120 serni-conic sunfaces illustrated, trailing edge 19 ooincides With the axis of the conic surface foiming blade 11 and similarly edge 16 coincides with the conic axis 0f blade 12. The adjacent pairs of these edges -are separated by equal (60) angles. This represents the preferred form 0f construction for obtaining maximum eificiency. It is, however, possible within the scope of 12h1's invention to employ bladps defining semi-oonic surfaces having greater or lesser obtuse apex angles, the important feature of the invention being the employment of -a pair of opposing semi-conic blade surfaces which gather fluid from 1:w0 cutting areas on opposite sides of fche shaft and =throw mhe two resulting streams of fluid into a Single stream in a direction aligned w1'th the axis of rotation and having a transverse =area substantially less than the sum 0f the outting areas. Thus, in eifect, the pair of blades cooperate together in acting upon the water or other fluid, to thrust =the fluid irom the propeller as a single, united, stream.

We claim:

1. A propeller which compn'ses a shaft rotatable Pai'ented Sept. 27, 1 sao about a central :axis .and a pair of identical blades, each formed to define a semi-conic surfiace having an obtuse apex angle, said blades being aflixed 10 said shaft at l;heir apices and lying on opposite sides cf said shaft with t=heir leading edges aligned 011 opposite sides 0f 5 said shaft penpendicular -to the axis 015 rotation of said shaft and wit.h their trailing edges extending from said shaf-t in the plane determined by said axis of rotation and the line of said leading eclges.

2. A ropeller according 10 claim 1 in Whl0h the 10 zipex angle of each said half-cone blade is 120.

.References Cited in the file of Ihis..patent UNITED STATES PATENTS Ferrero Mar. 6 1917 McNamara July 6, 1937 FOREIGN PATENTS Great Britain of 1889 Sweden Aug. l, 1923 France Jan. 11, 1926 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent N0. 2954083 September2'l', 1960 Olav A. Skarsten et a1.

It is hereby cerbified thao error ppears in ehe above numbered patenb requiring correction and that the seid Letters Patent should read es corrected below.

Column l lines 20 and 21, strike out "which is particul: provides an efficient propeller"; line 53, for "made in" read made 120 column 2, line 1, for Fig. l" read Fig. l), column 4, 1ine 8 list of references cited under "FOREIGN PATENTS", for the patent number "20,782" read 20,783

Signed and sealed this 6thday of June 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner Qlfi' Patents 

